I'm hoping that someone wouldn't mind taking a crack at the problems I'm having with my automatic 2002 Honda Civic EX. Originally, all I knew was that on warm/hot days, while driving, the RPM's would jump up, and my check engine light would come on, but then regulate itself and go back to normal. If it didn't go back to normal, the RPM's would drop to 0, temp gauge would drop to cold, and the check engine light would stay on.(Limp Home Mode??) I'd pull over, and my car would restart with no problems. Same thing happens multiple times before I make it home. No codes are being thrown at all, so mechanics haven't really been able to help me since it's intermittent. I was told that it could be the ignition switch. We replaced it, but that didn't fix it. We were looking around online and in the book for the car, and I've seen that it could be the Main Relay. We aren't very clear if the Main Relay and the PGM-FI Relays are the same things?? We took apart the glove box bracket, and heard clicks from the two PGM-FI Relays as the check engine light was going on and off. We replaced those, but it is still happening. We were assuming it had something to do with Fuel system or Delivery system, but still don't know....

I was finally able to take it to a mechanic while it was happening and he thinks it might have something to do with the transmission?? The green light around D on the dashboard when I'm in drive flickers and goes out before the check engine light goes on. He thinks that the clicking of the relay and check engine light are in response to whatever is causing the green light problem... This baffles everyone, esp since it only happens when its 70+ degrees outside. Can someone please help me???

 

With all those things going on with temp gauge, tach, and the flashing D, sounds like you have something going on with PCU. You can make sure that all the connections are firmly seated at the especially PCU. The flicker green drive light with a speedo problem is usually the Vehicle speed sensor. Are you sure the temp gauge drops to cold? Even the check engine light is off, you can still pulls the codes from memory.

 

Thank You for your reply!! The speedometer doesn't change at all, so I'm thinking it's probably not the Vehicle Speed Sensor. The temp gauge only drops to cold when the check engine light stays on. Thats when the RPMs drop to 0 and the temp gauge goes cold. I've had the codes checked at least 5 times, even by the "sophisticated" Honda dealership code reader, but it shows nothing. I had it checked with the check engine light on, and still showed nothing. I'm assuming (and hoping) thats its electrical and not the transmission. I'll try the PCU, and let you know... Thank You!

 

ChristieM - Hopefully you still receive e-mails from this post. Did you find out what was wrong with your civic? I have nearly the exact same problem and the Honda dealer can not figure out what to do - after 3 weeks of testing. Let me know!

 

I'm having the same problem as well. cant find the answer anywhere if you find anything out evans058 could you let me know. and if you heard anything from ChristieM.
Thanks

 

I don't have EXACTLY the same problem but maybe it's caused by the same thing.
-Gauges go down to 0, then bounce back again, rpms up and down
-Electric locks don't work

Did some research and my issue looks like it's the multiplex control module located in the dash fuse box. If you can't figure out what yours is you might want to try replacing that. It controls:

-Charging
-Horn
-HVAC (heating/cooling)
-Fans
-Wipers
-Power locks.